Lee Johnson admitted "home truths" were told after Latics lost 1-0 at Shrewsbury Town to a goal from old-boy Joe Jacobson in their rearranged npower League One match.
Latics' manager was unhappy with the performance of his new-look team as he made eight changes from Saturday's starting line up.
Johnson, who said he learned much from the game, explained: "I asked the players before the game whether they were ready to win the league.
"And I wanted to see whether they could show in their play and attitude that they can win the league.
"They didn't and couldn't so it is a lesson learned and there were some proper home truths which is good. We will see who reacts to them on Saturday.
"If you want to win a league or compete to win a league, you have to show in every game more than we did here. That performance wouldn't get you into the top ten and what I saw just confirmed what I already knew.
"We have a couple of players here who have been promoted from League One and I got them to speak as I did as I have also been promoted from it. I told them what it takes, and we didn't show that today."
Johnson added that Shrewsbury weren't great, but they were better than Latics pointing out had they raised their game by five-per-cent they would have probably won the game comfortably.
He added that it also underlined they cannot afford to lose key players from the team.
After the energy-sapping three wins in one week which secured League One survival, Johnson explained the changes ought to have given them "energy, dynamism and fresh legs" saying the night's events vindicated his decision to keep an unchanged line up in previous matches.
Latics' manager added, however, the league debuts for Joe Cooper and Danny Gosset were two positives to emerge from the game.
Cooper, who made his debut at right back, was joined in the starting line up by goalkeeper Alex Cisak, fit-again centre back Cliff Byrne, midfield man Bobby Reid, Carl Winchester and Cristian Montano while Jose Baxter and Kirk Millar were the front pairing.
Strikers Matt Smith and Lee Barnard were left at home with knocks picked up on Saturday while Dean Bouzanis, Connor Brown, Glenn Belezika, Robbie Simpson and Korey Smith stood down to the bench and David Mellor was rested.
With better finishing, both sides could have found the net in a goalless opening half.
Baxter could conceivably have scored a first half hat trick as he forced two excellent saves from home keeper Chris Weale while also seeing a header flash just past the upright in stoppage time.
Millar was also denied by a smart ssve from Weale as Latics were unable to find a route to goal.
The Shrews also had their chances, notably when Akwasi Asante burst clean through only to fire wide. Jon Taylor's low free kick also had to be turned round the post for a corner by Cisak.
Latics also had to rejig their side after only 25 minutes when Jonathan Grounds had to retire through a neck injury.
The breakthrough came in the 49th minute from former Latics' left-back Joe Jacobson with his first goal of the season.
Jean-Yves M'voto conceded a free kick on the edge of the box and Jacobson, also made captain for the night in the absence of Matt Richards, stepped up to bend the dead ball over the defensive wall and beyond the despairing dive of Cisak.
Latics lived dangerously as the Shrews had another goal ruled out for offside after Taylor set up Tom Bradshaw.
The diminutive Taylor burst clear and rounded Cisak before striking the upright from a tight angle and that was followed by a header from Connor Goldson narrowly clearing the crossbar.
Latics sent on Korey Smith for Winchester mid-half and then with 18 minutes Gosset became the second debutant of the night when he replaced Reid.
The Shrews continued to create chances as Taylor and Cameron Gayle both went close.
Latics only produced the occasional flicker, their best chance falling to Millar in the 88th minute when he had a goalbound shot blocked.
And not even seven minutes of stoppage time played by referee Eddie Ilderton could provide a way back into the game by Latics.
Shrewsbury Town (4-4-2): Weale; Gayle, Mambo, Goldson, Jacobson; Wildig (Woods 90+2), Summerfield, McGinn. Taylor; Asante (Parry 88), Bradshaw. Subs (not used): Anyon, Purdie, Richards, McAllister, Woods.
Latics (4-4-2): Cisak; Cooper, Byrne, M’voto, Grounds (Simpson 25); Croft, Winchester (K Smith 64), Reid (Gosset 72), Montano; Baxter, Millar, Subs (not used): Brown, Bouzanis, Hughes, Belezika.
The goal: Jacobson (49) for Shrewsbury.
Bookings: Gosset (79), M’voto (81) and Montano (90+4) for Latics.
Referee: Mr E Ilderton.
Attendance: 5,332 (347 visitors).